In many applications, it is desirable to split a signal into two or more parts and by way of example, two such applications will be described.
A first example is disclosed in U.S. Pat. No. 3,988,379 Clarke et al. and relates to a wideband receiving system able to eliminate in-band interference from a received wideband signal. The wideband receiving system has a multichannel filter arrangement comprising a broadband power splitter for splitting a received broadband signal into several subchannels and a series of narrowband bandpass filters, each associated with a different subchannel, for providing frequency delimited portions of the received signal in the subchannels. Means for detecting the presence of interference within each subchannel is also provided wherein subchannel(s) containing interference are disabled. The remaining subchannels are then recombined, providing a signal corresponding to the received signal with those portions of the received signal containing interference removed.
A second example is disclosed in U.S. Pat. No. 4,363,138 Franklin et al., also in which it is known to split a received spread spectrum signal in two subchannels and using bandpass filters, provide two different frequency delimited portions of the received signal which can be compared to each to other in order to despread the signal in a noisy environment.
Both U.S. Pat. Nos. 3,988,379 and 4,363,138 are however, a disadvantage of such conventional arrangements of splitting a signal is the degree of complexity of the filter arrangements necessary in order to provide sharply defined subchannels, especially when implemented with analogue filter circuitry.